A seat slide mechanism, which slides a seat in a forward and backward direction to suit a body frame of a person sitting on the seat, is provided at the seat on which an occupant of a vehicle is seated. For example, an invention disclosed in JP 2006-027329A is known as an invention of the seat slide mechanism. As shown in FIG. 2, the seat slide mechanism is configured by slidably fitting a pair of a first upper rail 12 and a second upper rail 12′, fixed to a lower surface of the seat, into a pair of a first lower rail 11 and a second lower rail 11′, fixed to a vehicle floor so as to extend in the forward and backward direction. A lock mechanism 20 is provided to lock sliding movement of the first upper rail 12 and the second upper rail 12′ relative to the first lower rail 11 and the second lower rail 11′, and a rod 51 is provided with an arm 81 projecting therearound. The arm 81 operates a release lever 18 releasing the lock of the lock mechanism 20. The rod 51 is rotatably supported by first and second holes 43 and 43′ of first and second side frames 41 and 41′, projecting respectively on the first and second upper rails 12 and 12′, through a first and second felts 63 and 63′. The first felt 63 is provided being pressed between a first vertical wall 42 and an arm 61 (a first flange member) of the rod 51, and the second felt 63′ is provided being pressed between a second vertical wall 42′ and a washer 62 (a second flange member) of the rod 51. These first and second felts 63 and 63′ prevent the rod 51 from moving in an axial direction, and further prevent noise, caused when the first flange portion 61 contacts with the first upper rail 12 and when the second flange portion 62 contacts with the second upper rail 12′.    Patent Document 1: JP2006-027329A